$ apt-get dist-upgrade -s
NOTE: This is only a simulation!
apt-get needs root privileges for real execution.
Keep also in mind that locking is deactivated,
so don't depend on the relevance to the real current situation!
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages have been kept back:
ffmpeg libavcodec-ffmpeg56 libavformat-ffmpeg56
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.

$ apt-get install ffmpeg libavcodec-ffmpeg56 libavformat-ffmpeg56 -s
NOTE: This is only a simulation!
apt-get needs root privileges for real execution.
Keep also in mind that locking is deactivated,
so don't depend on the relevance to the real current situation!
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
libavcodec-ffmpeg56 : Depends: libx265-59 (>= 1.7) but it is not installable
E: Unable to correct problems, you have held broken packages.